document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1206616>Question 1206616</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I'm having trouble figuring this out. <BR>\n" );
document.write( "The angles of elevation to an airplane from two points A and B on level ground are 55° and 72°, respectively. The points A and B are 2.8 miles apart, and the airplane is east of both points in the same vertical plane.\r<BR>\n" );
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document.write( "a) Find the distance between the plane and point B. (Round your answer to two decimal places.)<BR>\n" );
document.write( "(b) Find the altitude of the plane. (Round your answer to two decimal places.)<BR>\n" );
document.write( "(c) Find the distance the plane must travel before it is directly above point A. (Round your answer to two decimal places.) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #844182 by </B><A HREF=/tutors/aboutme.mpl?userid=math_tutor2020><B>math_tutor2020(3817)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=math_tutor2020><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=844182\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <font color=black size=3><BR>\n" );
document.write( "I'll focus on part (b) only.\r<BR>\n" );
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document.write( "Review this similar question<BR>\n" );
document.write( "<a  rel=nofollow HREF=\"https://www.algebra.com/algebra/homework/Triangles/Triangles.faq.question.1199063.html\">https://www.algebra.com/algebra/homework/Triangles/Triangles.faq.question.1199063.html</a><BR>\n" );
document.write( "On that solution page I provide the derivation of this formula<BR>\n" );
document.write( "h = d*u*v/(u-v)<BR>\n" );
document.write( "where,<BR>\n" );
document.write( "h = height or altitude of the object<BR>\n" );
document.write( "d = distance between observation points<BR>\n" );
document.write( "u = tangent of larger angle<BR>\n" );
document.write( "v = tangent of smaller angle\r<BR>\n" );
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document.write( "In this case,<BR>\n" );
document.write( "d = 2.8<BR>\n" );
document.write( "u = tan(72)<BR>\n" );
document.write( "v = tan(55)\r<BR>\n" );
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document.write( "So we can quickly determine the altitude to be:<BR>\n" );
document.write( "h = d*u*v/(u-v)<BR>\n" );
document.write( "h = 2.8*tan(72)*tan(55)/( tan(72) - tan(55) )<BR>\n" );
document.write( "h = <font color=red>7.46 miles approximately</font><BR>\n" );
document.write( "Make sure your calculator is in degrees mode.\r<BR>\n" );
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document.write( "Tutor Edwin has the right idea, but I'm not sure where he got the 53 degree angle from. It should be 55 instead. \r<BR>\n" );
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document.write( "Extra info:<BR>\n" );
document.write( "Multiply by 5280 to convert from miles to feet.<BR>\n" );
document.write( "7.46 miles = 7.46*5280 = 39388.8 feet<BR>\n" );
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